Geologic Map of Arizona in Not-Dead-Tree Format

Note from Kyle: A new contributor has entered the froth! I think he is smarter than I am…

We’ve all read Kyle’s rants against paper maps, and we’ve all seen some of the potential for online, digital mapping by using websites like MapQuest or software like Google Earth. So if we want to try and step away from producing flat, paper maps and want to be able to share our digital geologic data with each other, what kind of format are we going to use? The answer is that we’re going to need to learn to use map services.

Your users are desperate to get your data

What is a map service? Think of it this way: Your map and data exists on a computer somewhere that everyone can see over the Internet. Everyone wants to see your map data, but you can’t just open the barn doors and let them all tear into it. Think wolves starved by the longest, harshest New England winter suddenly turned loose inside the barn where your sheep have been warm, toasty and chubby for months. This just won’t do. Instead of a wild feeding frenzy, you need some organization. A map service provides organization by specifying how to ask for the data, and how it will be returned. In these terms, a map service lets the wolves have all the sheep they want, as long as they ask nicely.

This allows for a variety of client applications (for example your web browser, Google Earth, or ArcGIS Desktop) to provide an interface by which people can look at your map data. As long as an application knows how to ask the right questions, and what to do with the answers, it will be able to view the map.

Map services are an important step in moving our geologic maps off of paper and getting them online. They allow us to share both our data and our cartographic work with each other. Ever downloaded a “map package” that consisted of an indecipherable slew of files, databases, interchange formats, acronyms and cryptic field names? Well map services are the solution, providing not only an image of your map, complete with all the cartographic work you put into it, but also a simple interface for grabbing the data itself.

At the Arizona Geological Survey, we’ve put together a map service for the geologic map of the State of Arizona. You can view it here:

In the future we’ll be putting together more and more of these services, and including with them more information – photos, field notes, descriptions of important contacts and structures, etc. Perhaps the most intriguing part of all this though, is how easy it is to create these map services. If you have a functioning web server and have access to ArcGIS Server, then you have absolutely no excuse not to start figuring out how to use it. If you don’t have a web server or ArcGIS Server, well, stay tuned, because the AZGS is also working on putting together a software package, or “stack”, of entirely free, open-source applications that do very similar things to what ArcGIS Server can do. Our goal is to make it possible for everyone to begin exchanging maps and data using map services.

We did a little experimenting with MapServer and then began working with Deegree. I’ll take a closer look at GeoServer, but I think a lot of the framework has already been laid using Deegree. When things come together a bit more I’ll certainly put together a post about it!

I have a question about ArcGIS server if you have a second. A friend will be doing a live demo/survey of an interactive map she made. Since a classroom full of people will be logging onto her map, I was concerned that is might be too much for the system and suggested she download it to the hard drive like we do with our other web-related classroom activities. She wasn’t sure if that was possible since it was through an ArcGIS server and neither am I. I am unfamiliar with how the server interacts with the map.
Is it possible for her to download her map onto the hard drive and still have it be interactive? If not, is there something else she might be able to do to keep from bogging the system down (if there system is not able to handle a classroom full of users)?

I’m guessing that what you mean by “Interactive Map” is that your colleague has put together a web application — that is, a website that you look at in a web browser, which provides you with tools to zoom in and out, pan around, and identify features on the map. This application is not the same as a map service. The service is the map itself, and the web application is the tools or interface through which you view the map service.

If this is the case, then I’m afraid you can’t download it onto a drive to run for a presentation. It will only work when viewed on the internet.

If you’re going to try and present a map service that you’ve created, you need to think carefully about how exactly you intend to do it. Will you have an internet connection where you’re presenting? Do you want to view the map through a web-application type interface, or do you want to show it in Google Earth or ArcMap? If other people are going to be looking at it idependantly, what software are they going to use to see it? Of course, if there is ever any doubt about dynamic content for a presentation working, you’re probably best off taking a few screenshots and talking about the map service’s capabilities, rather than risk an embarassing flop.